1. Field of the Invention
The present invention relates to a portable light source apparatus which can be brought into work sites.
2. Related Background Art
Conventionally known as a technique in such a field is Japanese Patent Application Laid-Open No. HEI 8-329732. The light source apparatus disclosed in this publication has means for cooling a deuterium lamp. Namely, the deuterium lamp is accommodated in a light source block, whereas a vent hole formed in the light source block and a cooling fan are connected to each other by an air duct, so that cooling winds sent out from the cooling fan pass through the light source block, thereby indirectly cooling the deuterium lamp.
However, though the above-mentioned conventional light source apparatus is contrived such that the deuterium lamp is cooled with cooling winds, the deuterium lamp does not operate stably when simply cooled and may not achieve a desirable stability of output when cooled in excess. This results from the structure of the deuterium lamp, which maintains a low pressure state of {fraction (1/100)} atm or so therewithin, thus having a characteristic which is quite easily affected by temperature changes in the outside air. Conventionally, while the deuterium lamp is accommodated in the light source block, the light source block is utilized so as to be directly in contact with the outside air, whereby the deuterium lamp is quite susceptible to changes in the outside temperature in work sites, thus leaving a problem that it is difficult for the deuterium lamp to attain a stable output characteristic.
Japanese Patent Application Laid-Open No. HEL 8-233659 discloses means for directly cooling a deuterium lamp while in a state where the deuterium lamp is accommodated in a light source chamber. Japanese Patent Application Laid-Open HEI 9-27213 discloses one in which a xenon lamp, which does not require such minute temperature control as that in the deuterium lamp, is accommodated in a lamp house and is indirectly cooled by a cooling fan. Japanese Patent Application Laid-Open No. SHO 57-165811 discloses a light source apparatus configured such that a condenser lens is blown with cool outside air immediately after the lamp is lit. Japanese Utility Model Registration No. 2561305 discloses a detachable light source unit (lens barrel) in a light source apparatus.
In order to overcome the problems mentioned above, it is an object of the present invention to provide a portable light source apparatus which, in particular, is less likely to be affected by temperature changes in the outside air, so as to attain a very high stability in output.
This portable light source apparatus comprises a lamp box, secured within a housing, accommodating a deuterium lamp for generating a predetermined wavelength of light, and having a light exit opening for letting out the light emitted from the deuterium lamp; a power unit, secured within the housing, for driving the deuterium lamp; a cooling fan, secured to the housing, for generating a forcible air flow within the housing; and a light guide tube secured to the lamp box so as to extend the light exit opening of the lamp box.
This portable light source apparatus is an apparatus for lighting/blinking a deuterium lamp. The deuterium lamp does not operate stably when simply cooled. This is because of the fact that the deuterium lamp maintains a low pressure state (e.g., about {fraction (1/100)} atm) therewithin, thereby exhibiting an output characteristic which is quite susceptible to temperature changes. Therefore, such a deuterium lamp is accommodated in a lamp box and, at the same time, in a housing in order for the influence of temperature changes in the outside air to become very small. Namely, the deuterium lamp, which is susceptible to changes in temperature, is enveloped not only by the lamp box but also by the housing, thereby being accommodated in a double shield structure. Further, it has been known that ozone is generated when ultraviolet rays are emitted in the air. Therefore, in the present invention, the light guide tube for extending the light exit opening of the lamp box is provided, so that cooling winds do not traverse the ultraviolet rays. As a result, ozone is restrained from occurring in the part where the ultraviolet rays occur within the housing, whereby the emitted light is appropriately kept from fluctuating due to the occurrence of ozone.
Preferably, in the portable light source apparatus, a condenser lens is disposed within the light exit opening of the lamp box. When such a configuration is employed, the condenser lens can be built in appropriately and can be arranged so as to approach the deuterium lamp, so that a larger amount of light can be collected, whereby the light intensity increases.
Preferably, in the portable light source apparatus, the condenser lens is held and secured between the light guide tube and the lamp box. Such a configuration makes it easier to mount a condenser lens matching characteristics of the deuterium lamp, thereby enhancing the efficiency in operations and the degree of freedom in choosing condenser lenses.
Preferably, in the portable light source apparatus, the condenser lens is disposed within an extended opening of the light guide tube. When such a configuration is employed, the condenser lens can be built in appropriately and can be arranged so as to approach the deuterium lamp, so that a larger amount of light can be collected, whereby the light intensity increases.
Preferably, in the portable light source apparatus, the rear end of an adapter for an optical connector is inserted into the extended opening of the light guide tube from the front end side thereof such that the front end of the adapter is exposed from the housing. In this case, the adapter for the optical connector makes it easier to carry out optical connections in the outside of the housing, whereas a structure in which the ultraviolet rays are very hard to be influenced by cooling winds is attained within the housing, whereby optical output characteristics can be stabilized quite highly.